There is known, for example, a pitcher type water purifier which is generally used at home, is capable of purifying raw water up to 1 to 2 liter at one time, and can be kept in a refrigerator or the like as it is. As a pitcher type water purifier, there is a water purifier including an outer container, an inner container which is formed to be detachable from the outer container and to divide the inside of the outer container to a upper part and a lower part, and a water filter cartridge formed inside the inner container, for example. According to the pitcher type water purifier, a region of the outer container that is below the inner container is a purified water reservoir, and a region of the outer container that is above the inner container is a raw water reservoir.
When raw water is added to a raw water reservoir of the pitcher type water purifier, the raw water slowly passes through the water filter cartridge to be purified by virtue of its own weight, and then flows into the purified water reservoir.
As a water filter cartridge, a cartridge having activated carbon or a hollow fiber membrane bundle as a filtering material is known. For example, mention can be made of a water filter cartridge in which a hollow fiber membrane bundle is fixed on a bottom part in an approximately cylinder shape case to accommodate a filtering material and activated carbon is filled on the hollow fiber membrane bundle without being mediated by a partition member (Patent Literature 1).
According to the water filter cartridge, raw water is filtered by a hollow fiber membrane only after being in contact with activated carbon. As such, even when there are proliferating microbes in the active carbon layer, the microbes are not incorporated in purified water. Furthermore, due to the absence of a partition member, filtration flow rate is high and raw water can be purified smoothly.